Vehicle collision damage reduction system

ABSTRACT

A vehicle collision damage reduction system is provided. The system works by detecting the relative speed between the vehicle and an object, such as another vehicle. A danger level is calculated based on parameters such as speed and distance to the object; the danger level could be at an “emergency level” or at some lower level. Based on the danger level, different corrective measures and the degree of the corrective measures can be adjusted to attempt to minimize occupant injury. For example, the airbag can be adjusted to better protect the occupant, a pre-tensioner can be activated at a certain level, and the inclination of a child restraint seat may be adjusted as well.

This is a Divisional Application of application Ser. No. 09/633,142,filed Aug. 4, 2000, which in turn claims priority to and the benefit ofU.S. Provisional Patent Application Serial Nos. 60/147,135; 60/147,136;60/147,137; 60/147,138; and 60/147,150, all of which were filed on Aug.4, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle collision damage reductionsystem, and more specifically, it relates to a system for minimizinginjury to the occupant suffered in a vehicle collision. This systemworks to detect an unavoidable collision during vehicle travel justprior to the collision and to deform the vehicle's structure in thecollision, thus absorbing enough collision energy to ensure adequatesafety space for the occupant and to enable occupant restraintprotection devices to operate effectively.

2. Description of the Related Art

Various vehicle structures and occupant protective devices have beenpreviously developed to attempt to reduce injury to occupants in avehicle collision. The features of and problems in conventional vehiclestructures and occupant protective restraining devices generally will bedescribed below.

Vehicle Structure for Damage Reduction in Collision

To achieve reduction in occupant injury in a collision, it is firstimportant that a safety space for an occupant be secured in the vehiclestructure and that the impact applied to the occupant be reduced in avehicle collision and in a secondary collision.

Vehicle Structure

A conventional vehicle structure of a passenger vehicle can be designedkeeping in mind several assumptions regarding various collisionconditions for occupant safety. In general, a crushable zone is providedin the front and rear of a vehicle structure so as to absorb impactreliably in a collision while the structural rigidity of the cabinportion as a safety space is increased for the safety of the occupants.For example, in a head-on collision, front members such as front crossmembers, side members, and vehicle frames are designed to be crushed insequence to receive collision energy and thereby absorb the energy so asto minimize the deformation and rupture of the cabin portion.

However, when the collision speed is higher than the assumed value fordesigning members of various parts and the vehicle frame, the cabin canbe greatly deformed so that an occupant restraint protective device inthe cabin might be in danger of being injured and thereby not protectingthe occupant properly against the applied collision energy. Also, impactenergy absorption by the vehicle might be insufficient, depending on theform of the collision.

Steering Mechanism for Impact Absorption

In certain known steering mechanisms, an impact absorption mechanism maybe included which undergoes displacement in the front direction when apredetermined load is applied thereto, Such steering mechanism may beassembled on the assumption that a steering wheel located in front of anoccupant might be an element capable of injuring the occupant in acollision, e.g., the occupant's torso or other areas, when the occupantcollides with the steering wheel in the secondary collision followingafter the initial vehicle collision. A collision “energy absorbing”structure (an “EA” structure) also may be assembled in an alignmentdevice of the steering mechanism or within a column shaft so as toattempt to reduce injury.

Since EA load characteristics for this structures are designed at thistime to assume that the occupant is of AM 50% (i.e., the standard sizeof adult male) colliding under a predetermined condition, theseassumptions may be not the most suitable for occupants having variousphysiques and sitting in various states and for various collision statesto best attempt to reduce occupant injury. A more variable system isneeded.

Occupant Restraint Protective Devices for Reducing Injury in a Collision

As a typical example of an occupant restraint protective device, aseatbelt device, an airbag, and a child seat are known and becoming widespread. However, they have the following undesirable characteristics:

In a conventional seating position, an occupant is free to assumedifferent seating postures. The occupant even may have an unsuitableposture for securing him safely by a seatbelt or an airbag. For example,the following seating postures are not the best for providing adequatesafety to the occupant:

(1) sitting excessively close to the steering wheel

(2) sitting with an excessively inclined seat back

(3) lower seat surface at the front than that at the rear.

It is preferable that the occupants having the posture be corrected tohave proper posture and a proper position for being properly restrained.

In a conventional seatbelt take-up device with a pre-tensioner, thepre-tensioner is activated by determining a collision scale from theacceleration and the speed-change rate detected by a crush detectingsensor, etc. When a head-on collision of a vehicle occurs, for example,a difference of relative speed between an occupant and the vehicleoccurs in a slight delay period just after the collision because of theinertia force applied to the occupant when the vehicle speed is zero. Inorder to drive the pre-tensioner of the seatbelt for restraining theoccupant moving within such a slight time difference, a large drivingforce is needed. Therefore, in a conventional pre-tensioner, a strongand heavy driving source large in size is used, so that a miniaturizedand lightweight seatbelt take-up device having the pre-tensionerassembled therein is difficult to be achieved.

Child Seat

In a conventional child seat (referred to as a “CRS” or “Child RestraintSeat”), because an infant is seated thereon in a collision, arestraining effect is changed in accordance with the installing state ofthe CRS and the reclining state. For example, when the CRS is installedforward-facing in an upright position in a collision, the impact appliedto the infant is substantially restrained by buckle and belt portions.In contrast, in a reclining position, it is assumed that part of therestraining load applied to the belt can be relieved by the seat surfacebecause the seat surface is formed to serve as a supporting facerelative to the colliding direction.

On the other hand, when a collision occurs with the CRS installedrearward-facing in a reclining position, although an infant is supportedby a seat back portion, the infant starts to slide in the collisiondirection because the inclination angle is small, so that the infant isrestrained in the loaded state on a shoulder belt. However, when the CRSis in an upright position, it is assumed that the load is substantiallysupported by the seat back because of the large angle of inclination.

Improving Damage Reduction in Collision by Using a Collision PredictingSensor System

To attempt to overcome some of these problems, a collision safety systemhas been under development in which a collision is unavoidable bydetermining the distance between the vehicles and the acceleration stateby using a non-contact distance sensor using, inter alia, radio waves(millimetric waves), a laser, ultrasonic waves, acoustic sound waves,visible light, or the like. In such a system, for example, an embodimentis considered in that the occupant restraint protective device starts tofunction just before a collision in accordance with an emergency levelwhich is determined in stages by a collision danger level determiningcircuit arrangement in the system, which utilizes the above-mentionednon-contact distance sensor as a collision predicting sensor attached tothe front end of an own vehicle for detecting a running speed of the ownvehicle, a distance and a relative speed to another vehicle or anobstacle (object to be impacted), and so forth. Some of the applicantshas developed a technique disclosed in Japanese Unexamined PatentApplication Publication No. 9-132113 as a criterion of assessing variousdanger levels with respect to the severity of the impending collision,which is hereby incorporated herein its entirety. By utilizing such adeveloped technique, a more advanced damage reduction method from acollision is achieved.

SUMMARY OF THE INVENTION

As mentioned above, when a collision is detected just before thecollision, the above-mentioned vehicle structure and the occupantrestraining and protecting device respectively serve the followingfunctions at a vehicle collision, thereby, injury reduction may beachieved.

Safety Vehicle Structure

When the collision speed is large, the energy absorbing capacity isincreased corresponding to the speed. Besides a full-lap collision, evenwhen an offset collision having a lapping rate of 50% or less occurs,the collision energy is efficiently absorbed by only the vehicle part onthe collision side. “Lapping rate” means the amount which a vehiclecollides with and overlaps an object or vehicle upon a collision.

Before a secondary collision occurs just after a vehicle collision, thecapacity to absorb occupant collision energy is increased. For example,the distance between an occupant (driver) and the steering wheel isincreased without sacrificing steering operability, thereby minimizinginjury to the torso and/or the head of the occupant against the steeringwheel during the collision. In order to reduce damage of occupantshaving various physiques and seated postures, the EA loadcharacteristics are preferred to be capable of being varied.

Occupant Restraining and Protecting Device: Seat-Adjusting Mechanism

When an occupant has an undesirable seating posture, the posture isdesired to be properly corrected so that the occupant can be properlyrestrained and protected by the seatbelt device and the airbag. Thereby,even when an occupant has proper seating posture, the restrainingfunction can be furthermore improved. When the object detecting meanssuch as the collision predicting sensor is used in the correctingoperation, sufficient operating time for the device can be secured andthe correction can be performed by taking the collision danger levelinto consideration. In this way, the restraining and protecting meanscan function in a moderate mode of operation, depending on thesituation, without always using a momentary, actuating high-powerdriving device.

Seatbelt Pre-Tensioner

In order to drive the pre-tensioner of the seatbelt so as to restrain anoccupant within a short time before the displacement of the occupantjust after the collision, high-power driving force is required. However,when the object detecting means such as the collision predicting sensoris used in the correcting operation, sufficient operating time for thedevice can be secured and the correction can be performed by taking thecollision danger level into consideration. In this way, the restrainingand protecting means can function in a moderate mode of operation,depending on the situation, without always using a momentary actuatinghigh-power driving device. Therefore, the pre-tensioner device can beminiaturized and also can provide very effective protection thatrestrains an occupant before the movement.

CRS Reclining Mechanism

When a collision occurs when a CRS is installed to the seat, the variousreclining positions of the CRS can be corrected to have desired oroptimum posture for minimizing collision injury, so that impact appliedto an infant at the collision is dispersed over a more wider area inorder to support the infant. When the object detecting means such as thecollision predicting sensor is used in the correcting operation,sufficient operating time for the device can be secured and thecorrection can be performed by taking the collision danger level intoconsideration. In this way, the restraining and protecting means canfunction in a moderate mode of operation, without always using amomentary, actuating high-power driving device.

The above-mentioned functions may be achieved by the present invention.

In accordance with a first aspect of the present invention, there isprovided a vehicle collision damage reduction system comprising at leastone object detecting means for sequentially detecting distanceinformation to an object to be impacted moving relatively, and collisiondanger level determining means for determining a collision danger levelso as to output collision predicting information by sequentiallydetecting the distance information; collision energy absorbing means ina vehicle structure formed to support part of the vehicle structure inadvance for absorbing collision energy applied thereto in a collision;and controlling means for outputting an operational command, before thecollision, to the collision energy absorbing means in a vehiclestructure on the basis of the collision predicting information obtainedfrom the object detecting means or the collision danger leveldetermining means.

Preferably, the collision energy absorbing means in a vehicle structureis introduced as part of the vehicle structure in advance of an airbagand formed to support part of the vehicle structure. The airbag can beinflated, before a collision, by an operational command from thecontrolling means and deforming so as to absorb the collision energyapplied thereto when the vehicle structure deforms at the collision.

The expansion rate or the energy absorbing amount of the airbag for thevehicle structure may be preferably changed in stages in response to thecollision danger level based on the collision predicting informationobtained from the collision danger level determining means.

In accordance with a second aspect of the present invention, there isprovided a vehicle collision damage reduction system comprising at leastone object detecting means for sequentially detecting distanceinformation to an object to be impacted moving relatively, and collisiondanger level determining means for determining a collision danger levelso as to output collision predicting information by sequentiallydetecting the distance information; collision energy absorbing means fora vehicle occupant for absorbing collision energy applied to an occupantin a secondary collision following a vehicle collision; and controllingmeans for outputting an operational command, before the collision, tothe collision energy absorbing means for a vehicle occupant on the basisof the collision predicting information obtained from the objectdetecting means or the collision danger level determining means.

The collision energy absorbing means for a vehicle occupant may bepreferably steering column shortening means introduced in part of asteering column or a shaft to be shortened in the axial direction,before a collision, by an operational command from the controllingmeans, so as to increase the distance between the occupant and thesteering column or a shaft.

Load characteristics of the collision energy absorbing means for avehicle occupant introduced in part of a steering column or a shaft mayalso be preferably changed in stages in response to the collision dangerlevel of the collision predicting information obtained from thecollision danger level determining means.

Preferably, a vehicle collision damage reduction system furthercomprises occupant seating information detecting means for detectingphysique and a seating state of an occupant seated in a seat so as tooutput seating state information to the controlling means, wherein theoperational amount of the collision energy absorbing means for a vehicleoccupant is established, before a collision, on the basis of the seatingstate information obtained by the occupant seating information detectingmeans. The “seating state” is defined as the condition how the occupantis seated in a seat, such as how close to the steering wheel, how farthe seat back is inclined, etc.

In accordance with a third aspect of the present invention, there isprovided a vehicle collision damage reduction system comprising at leastone object detecting means for sequentially detecting distanceinformation to an object to be impacted moving relatively and collisiondanger level determining means for determining a collision danger levelso as to output collision predicting information by sequentiallydetecting the distance information; a seat adjusting mechanism capableof adjusting seat sliding, reclining, and seat height of a seatindependently or simultaneously; controlling means for outputting anoperational command of a predetermined seat adjustment amount to theseat adjusting mechanism on the basis of the collision predictinginformation obtained from the object detecting means or the collisiondanger level determining means; and occupant seating informationdetecting means for detecting physique and a seating state of anoccupant seated in a seat so as to output the seating information to thecontrolling means.

Preferably, the seat adjustment amount of the seat adjusting mechanismis changed in stages, before a collision, in response to the dangerlevel of the collision predicting information obtained from thecollision danger level determining means.

Preferably, the seat adjustment amount of the seat adjusting mechanismis established, before a collision, on the basis of the seatinginformation obtained from the occupant seating information detectingmeans for detecting physique and a seating state of an occupant seatedin a seat.

In accordance with a fourth aspect of the present invention, there isprovided a vehicle collision damage reduction system comprising at leastone of object detecting means for sequentially detecting distanceinformation to an object to be impacted moving relatively, and collisiondanger level determining means for determining collision danger level soas to output collision predicting information by sequentially detectingthe distance information; a seatbelt pre-tensioner for a seatbelttake-up device of a seat; controlling means for outputting anoperational command of webbing retraction in a predetermined amount tothe seatbelt pre-tensioner on the basis of the collision predictinginformation obtained from the object detecting means or the collisiondanger level determining means; and occupant seating informationdetecting means for detecting physique and a seating state of anoccupant seated in a seat so as to output the seating information to thecontrolling means.

At this time, it is preferable that the webbing take-up amount of theseatbelt pre-tensioner be changed in stages, before a collision, inresponse to the danger level of the collision predicting informationobtained from the collision danger level determining means.

The webbing retracting amount of the seatbelt pre-tensioner may also bemore optimally established, before a collision, on the basis of theseating information obtained from the occupant seating informationdetecting means for detecting physique and a seating state of anoccupant seated in a seat.

In accordance with a fifth aspect of the present invention, there isprovided a vehicle collision damage reduction system comprising at leastone object detecting means for sequentially detecting distanceinformation to an object to be impacted moving relatively, and collisiondanger level determining means for determining collision danger level soas to output collision predicting information by sequentially detectingthe distance information; a child seat installed to a seat in apredetermined installing state and having a reclining angle to beadjustable independently or simultaneously; controlling means foroutputting an operational command of a predetermined adjustment amountof the reclining angle to the child seat on the basis of the collisionpredicting information obtained from the object detecting means or thecollision danger level determining means; and occupant seatinginformation detecting means for detecting the child seat installed to aseat so as to output the installing information to the controllingmeans.

At this time, it is preferable that the adjustment amount of thereclining angle of the child seat be changed in stages, before acollision, in response to the danger level of the collision predictinginformation obtained from the collision danger level determining means.

The adjustment amount of the reclining angle of the child seat may alsobe preferably established, before a collision, on the basis of theseating information of the child seat obtained from the occupant seatinginformation detecting means for outputting the installing information ofthe child seat to the controlling means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system diagram showing an embodiment of a vehicle collisiondamage reduction system.

FIG. 2 is a block diagram showing a system structure having one bodyairbag in the vehicle collision damage reduction system shown in FIG. 1.

FIG. 3 is a block diagram showing a system structure having two bodyairbags in the vehicle collision damage reduction system shown in FIG.1.

FIG. 4 is a graphical representation showing changes in the operationalstate of a safety vehicle structure and an occupant restraining andprotecting device in the vehicle collision damage reduction systemaccording to the present invention.

FIGS. 5a to 5 c are representations schematically showing operationalstates of the safety vehicle structure in a collision (a body airbag,steering column shortening means, and a steering column EA mechanism) inthe vehicle collision damage reduction system shown in FIG. 1.

FIGS. 6a to 6 c are schematic representations of the operational statesshown in FIGS. 5a to 5 c when viewed from the plane, respectively (1:body airbag).

FIGS. 7a to 7 c are schematic representations of the operational statesshown in FIGS. 5a to 5 c when viewed from the plane, respectively (2:body airbag).

FIGS. 8a and 8 b are charts of EA load characteristics set in a steeringcolumn.

FIG. 9 is a representation of the schematic structure and theoperational state of a seat adjusting mechanism.

FIGS. 10a to 10 c are characteristic charts of the corrective states setin the seat adjusting mechanism.

FIG. 11 is a representation of the schematic structure and theoperational state of a seat belt pre-tensioner.

FIGS. 12a and 12 b are representations of the schematic structure andthe operational state of a child seat.

FIGS. 13a and 13 b are schematic representations of the fixed state andthe state of the corrective operation of the child seat.

FIGS. 14a and 14 b are schematic representations of the fixed state andthe state of the corrective operation of the child seat.

FIGS. 15a and 15 b are characteristic charts of the corrective statesset in the child seat.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of a vehicle collision damage reduction system accordingto the present invention will be described below with reference to theattached drawings.

FIG. 1 is a perspective system diagram showing a perspective structureof a vehicle collision damage reduction system according to the presentinvention, which is introduced to a passenger vehicle. A safety vehiclestructure and a structure of occupant restraining and protecting meansas the vehicle collision damage reduction system will be describedbelow.

As shown in FIG. 1, in the front face of a vehicle 1, a non-contactdistance sensor is provided as an object detecting means. Thisnon-contact distance sensor uses radio waves (millimetric waves), alaser, ultrasonic waves, acoustic sound waves, infrared rays, visiblelight, or the like. In particular, a distance sensor utilizing radar bymillimetric waves is difficult to be affected in measuring by externalperturbations in comparison with other signal waves to thereby obtainmeasured data with high accuracy constantly. The distance data from theobject detecting means 10 are input into controlling means 11 (referredto as an ECU 11 below, ECU: Electrical Control Unit), which is installedin part of the cabin where it is typically little affected by acollision. The ECU 11 is formed of a known processing circuit as ahardware structure and performs signal processing of a predeterminedinput signal so as to output a predetermined operational command to eachof driving means. The ECU 11 also serves as a collision danger leveldetermining means, which will be described later, so as to determine thedanger level by signal processing of a predetermined detected signal. Ata predetermined position of the vehicle 1, a body airbag 20, a steeringcolumn shortening means 30, an EA load characteristics changing means36, which is a column energy absorbing means, are provided as vehiclesafety structures. Within the cabin 3, a seatbelt device 45 and anoccupant airbag 60 are provided as occupant restraining and protectingmeans for protecting an occupant “P” while on a rear seat “4B”, a CRS 71is installed. In addition, a seatbelt for fixing the CRS 71 is includedbut is not shown in each of the drawings.

FIG. 2 is a block diagram showing this entire system structured byconcentrating on the ECU 11 shown in FIG. 1. As is shown together inFIGS. 1 and 2, each driving means of the body airbag 20 functions as thesafety vehicle structure, the steering column shortening means 30functions as an occupant collision energy absorbing means, the EA loadcharacteristics changing means 36 that is the column energy absorbingmeans, a seatbelt pre-tensioner 40 functions as the occupant restrainingand protecting means, a seat adjusting mechanism 50, an occupant airbag60, and a reclining mechanism 70 of the CRS 71 are connected to the ECU11 that is a controlling means as hardware in this system in order toreceive an operational command.

In addition, as shown in FIG. 1, the pre-tensioner 40 is built in aconventional seatbelt take-up device 42. Also, plural driving portions(not shown) are provided within a seat 4 for the seat adjustingmechanism 50. Furthermore, the reclining mechanism 70 of the CRS 71 isintroduced to the CRS 71 installed to a seat surface and is to beoperative when a weight sensor 81 as occupant seating informationdetecting means 80 and driving means 72 provided in the CRS 71 areconnected to each other by signals.

In the seat 4 (referred to as numeral 4 when the front and rear seatsare not distinguished) and the cabin 3, occupant detecting sensors (willbe described later) are provided as various occupant seating informationdetecting means 80. A detecting signal from each of these sensors issent to the ECU 11 as an output-signal informing of occupant-seatinginformation. The occupant seating information detecting means 80comprises various sensors for detecting the seating state of an occupantso as to obtain information for properly operating each of the occupantrestraining and protecting means in response to the seating state. Forexample, a weight sensor 81, a seat-sliding sensor 82, a reclining angledetecting sensor 83, and a seat-face inclination detecting sensor 84,are built into the seat 4. Detected signals from these sensors areprocessed by computations in a signal processing unit of the ECU 11thereby to establish the required correcting amount (sliding amount,angular amount, etc.) and the restraining amount based on thecomputation results so as to output a command to each of the restrainingand protecting means.

Each structure and function of the safety vehicle structure, theoccupant collision energy absorbing means, and the occupant restrainingand protecting means will be described with reference to the attacheddrawings.

FIG. 4 is a graphical representation showing changes with the passage oftime in operational quantities and characteristics such as operationaltiming and a load when each part operates during the time from thecollision predicting stage until after the collision.

Establishment of Collision Predicting Level by the Collision DangerLevel Determining Means

The degree of collision danger is determined based on the distanceinformation obtained from the object detecting means 10 in the ECU 11functioning as the collision danger level determining means 12. In orderto reduce collision damage, for example, when an “emergency level” isdetermined from the collision predicting information, it is importantthat the injury generated in a collision be minimized. As shown in FIG.1, when a relative speed between the vehicle 1 and an object to beimpacted 8 (depending on running conditions, the object can be either avehicle running in the opposite direction, a following vehicle, or astationary object) is determined. When the value reaches more than apredetermined value, this means that both will probably collide witheach other without avoiding the collision. If the collision scale can bepredicted before the collision so as to output a signal for securelyoperating the safety vehicle structure and the occupant restraining andprotecting means in response to these conditions, the occupant “P” canbe securely restrained and protected by such a structure and by meanswhich are driven with a small driving force, not with a high-outputdriving device, in the collision. Large energy absorbing capacity of thevehicle 1 can also be achieved.

When the relative speed between the vehicle 1 and the object to beimpacted 8 is large (for example, more than 20 Km/h) while the distanceto the object to be impacted is too small to avoid a collision (forexample, not more than 2 m), which is an example of the above-mentioned“emergency level”, a great probability of a collision is considered.These determinations are performed in the collision danger leveldetermining means 12, which is the signal processing unit of the ECU 11as hardware, by computation of the signal from the object detectingmeans 10. The determined danger level as a result of the computation isapplied to any one of plural levels in stages so as to output commandsof operational amount and operational timing in response to the level.

Safety Vehicle Structure: Body Airbag

The structure and function of the body airbag 20 as vehicle structurecollision energy absorbing means will be described with reference toFIGS. 5 and 6. In this embodiment, the body airbag 20 is described as anairbag provided in an engine room side of a partition wall 5 dividingthe front engine room 2 and the cabin 3 of the vehicle 1. The bodyairbag 20 is introduced into part of the vehicle structure in advanceand functions to absorb the impact energy applied to the vehicle 1substantially at a head-on collision by employing when the collision ispredicted in advance so as to support part of the deforming vehicle.

The body airbag 20 is provided in the engine room 2 side of thepartition wall 5 dividing the cabin 3 and the front engine room 2 whichfunctions as a crushable zone of the front of the vehicle 1, and mountedto part of a side member 6 b in the partition wall 5 side. As shown inFIG. 6b, the body airbag 20 is accommodated in an expandable telescopiccase 21, which is fixed to part of the front face of the partition wall5.

A bag body 22 of the body airbag 20 is a balloon-bag-shaped body sewn ofcloth-made base fabric and connected to gas generating means (notshown), the bag body 22 being inflatable by gas from the gas generatingmeans. The bag body 22 functions to increase the volume of the case 21by deploying within the case 21, in which it is accommodated. The gasgenerating means is capable of generating gas at higher pressurecompared with that of the occupant airbag. Since the inflated bodyairbag 20 is not brought into contact with an occupant, not like theoccupant airbag, parts for protecting the occupant safely, such as afilter in the gas generating means, can be omitted. As a structure ofthe bag body 22, a resisting pressure bag formed of thick rubber basefabric with reinforcing metallic mesh laminated thereon in layer may beused without accommodating in a predetermined case. Furthermore, anexpanding (elongating) structure, in which a metallic or resin casehaving a cloth or rubber airtight bellows provided in part of the caseis supplied by gas so that the bellows is elongated, can be included inthe concept of the airbag according to the present invention.

The operation of the body airbag 20 will be described with reference toFIGS. 5 and 6. When an obstacle is positioned so as to decrease therelative distance to a vehicle running at the velocity “V_(v)” existsahead of the vehicle, if the relative velocity “V_(r)” between them ismore than 20 km/h, for example, while the distance “D” is acollision-unavoidable distance, for example, not more than 2 m (about 20ms before the collision is assumed), the ECU 11 outputs an operationalsignal to deploy the body airbag 20 to an inflator as the gas generatingmeans of the body airbag 20, on basis of an information signal obtainedfrom a collision predicting sensor as the object detecting means 10. Thebody airbag 20 is inflated by the gas supplied by the inflator based onthe operational signal, so that the volume of the case 21, in which thebody airbag 20 is accommodated, is increased, as shown in FIGS. 5b and 6b. As to the operational timing, the expansion starts at about 10 msbefore the collision and continues for about 20 ms after the collision.Therefore, when the body airbag 20 is completely deployed, as shown inFIGS. 5c and 6 c, collision energy is absorbed by elastic deformation ofthe case 21 and deformation of the bag body 22 when parts such as anengine 2A and a transmission part move rearward in the process of thecrushing of the front crushable zone of the vehicle 1 after thecollision. Thereby, efficiency in deformation of the crushable zone islargely improved compared with that of a conventional vehicle structure,so that deformation of the cabin 3 and impact applied to an occupant “P”inside can be substantially reduced (see FIG. 5c).

FIGS. 6a to 6 c are schematic representations showing statescorresponding to FIGS. 5a to 5 c when viewed from the plane. As is shownin these drawings, at a fully overlapped serious head-on collision, afront cross member 6 a and the right and left side members 6 b connectedthereto are largely deformed, so that the engine 2A and other equippedparts in the engine room 2 move rearward by following the deformationwhile, as shown in FIG. 6c, the body airbag 20 deploying in the frontface of the partition wall 5 deforms so as to support these parts byreceiving them to thereby absorb the collision energy to be transmittedto the cabin 3 by its deformation stroke.

On the other hand, FIG. 3 is a block diagram showing the structures ofside body airbags 20R and 20L independently assembled into side members6R and 6L on the right and left (FIG. 6a), respectively. FIGS. 7a to 7 care schematic representations illustrating how the safety vehiclestructure with the above elements works from the collision predictinguntil operation of the airbag and finally the collision. As is shown inFIG. 3 and FIGS. 7a to 7 c, these side body airbags 20R and 20L can beindependently operated in response to collision predicting sensors 10Rand 10L arranged to the right and left of the vehicle 1 as the objectdetecting means 10. That is, as shown in FIG. 7b, upon an off-setcollision, in which only the collision predicting sensor 10R, one of thecollision predicting sensors, predicts the “emergency level”, the sidemember 6R, which is the side to be impacted, will be greatly crushed sothat the engine 2A and other equipped parts in the engine room 2disposed to the right of the vehicle 1 are substantially deformed,whereas a bag 22 arranged in a case 21R of the body airbag 20R in theside member 6R side is inflated before the collision, as shown in FIGS.7b and 7 c. Thereby, the collision energy can be efficiently absorbed inthe collision side. Also, the body airbag 20 shown in FIG. 6a is usedtogether to thereby prevent the deformation from affecting on the cabin3 side while energy absorbing capacity of the front of the vehicle 1 ina collision is increased to thereby reduce damage to a pedestrian incase of a collision to the pedestrian.

Occupant Collision Energy Absorbing Means. Steering Column ShorteningMeans, EA Load Characteristics Changing Means

FIGS. 5a and 5 b schematically show the steering column shortening means30 assembled in the vehicle 1. In this embodiment, a known telescopicmechanism (not shown) introduced to a steering column 31 is used as thesteering column shortening means 30. That is, the telescopic mechanismmovable in a predetermined stroke of 50 to 100 mm is provided in thesteering column 31. When a collision is predicted, an operational signalfrom the ECU 11 is received, thereby, the column is shortened by “Δc” inthe axial direction “S” (see FIG. 5b) by driving a driving unit(explosives, a motor, and a spring, all not shown) and so forth with thetelescopic mechanism unlocked. As the operational timing, the shorteningstarts at about 10 ms before the collision and finishes in about 20 ms.Thereby, the distance between an occupant (driver) and a steering wheelis increased so that force which the occupant receives in moving forwardby the-collision impact against the steering wheel can be reduced. Inaddition, as the steering column shortening means 30, the entire lengthof the column may also be shortened by bending an arm of a column linkmechanism.

A damage reduction technology has been conventionally known in thatenergy absorbing means is provided in the steering column 31 in case ofan occupant “P” falling over the steering wheel 33 via the airbag in acollision (see FIG. 1). For example, the column is shortened in theaxial direction by deforming a bellows, a steel mesh, or the like in theaxial direction while maintaining the steering functions. In thisembodiment, the EA load characteristics are changed on the basis of thecollision scale and the danger level detected by the object detectingmeans 10 or the collision danger level determining means 12 and also onthe basis of the occupant physique obtained from the occupant seatinginformation detecting means 80. FIG. 8a shows an example of settings ofcharacteristics in the column EA load characteristics means (not shown)corresponding to the collision scale (intensity of the collision)detected by an impact sensor such as an acceleration sensor. The loadcharacteristics may be changed according to one or plural quantitativethreshold values established, and the EA load characteristics may alsobe established in response to changes obtained by multiple times ofdetection.

It is also preferable that the EA load characteristics be changed by theEA load characteristics changing means 36, which is the energy absorbingmeans, in consideration of the occupant physique. As the occupantseating information detecting means 80, he weight sensor 81, theseat-sliding sensor 82, an occupant position detecting sensor, a visionsensor (image picking up sensor), or the like is provided in apredetermined position in the seat 4 or the cabin 3. The informationsignal obtained from the sensor is output to the ECU 11 to besignal-processed therein. FIG. 8b shows an example of settings ofcharacteristics of the column EA load characteristics corresponding tothe occupant physique. The load characteristics are set according to oneor plural threshold values established (for example, AF 05%, AM 50%, AM95%) AFO5% means “small size of adult female”. It is also preferablethat, since the moving timing and the displacement of an occupant in acollision differ largely on whether the seat belt is fastened or not,the EA load characteristics can be set in response to each of thesecases.

Seat Adjusting Mechanism

FIG. 9 is a schematic system diagram showing the schematic structure ofthe seat adjusting mechanism 50, which performs an operation to correctthe posture of each part of the seat during the predicting stage, andshowing the relationship between sensors 81, 82, 83, and 84 as theoccupant seating information detecting means 80 to achieve the posturecorrective operation. In a power seat, there are conventionally provideda seat sliding mechanism 51, a seat back reclining mechanism 52, and aseat height adjusting mechanism 53, which are individually orsimultaneously operable by an occupant via a concentrated remote switch.Furthermore, in each part of the seat, there are provided the weightsensor 81, the seat sliding sensor 82, the reclining angle detectingsensor 83, and the seat face inclination detecting sensor 84. Eachdetected signal is input to the ECU 11 as the occupant seatinginformation. Accordingly, when the above-mentioned undesirable seatingstates are confirmed according to the occupant seating information, thefollowing posture corrective operations are generally performed afterobtaining a positive collision predict determination:

(1) Slide the seat to the rear end (or a predetermined intermediateposition).

(2) Raise the reclined seat back to the upright position (at apredetermined angle).

(3) Tilt the seat face sloping down forward to be slightly slantedrearward.

The angular correction is performed by controlling and operating knowndriving mechanisms, such as a electrical motor, a gear mechanism drivenby an oil pressure jack, a wiring mechanism via pulleys, and a linkmechanism, by an operational signal from the ECU 11.

FIGS. 10a to 10 c are control characteristic representations showingcorrective operational amounts of various parts of the seat establishedaccording to the danger level determined by the collision danger leveldetermining means 12 in the collision predicting stage. In the seatadjusting mechanism 50, the “emergency level” (when the relativevelocity between an own vehicle and an object to be impacted is morethan a predetermined speed, 10 to 20 km/h for example, while beingcollision-unavoidable by the driver's operation) is established as onethreshold value. Furthermore, an intermediate setting position (angle),which is not such an emergency level, may be established as a secondthreshold value. A seat position, a reclining angle, inclination of theseat face, and so forth may also be sequentially changed on the basis ofcomputation of the relative velocity and the relative distance obtainedby multiple times of detection.

Seatbelt Pre-Tensioner

FIG. 11 is a schematic system diagram showing the seatbelt pre-tensioner40, which performs the retracting operation of the webbing in thepredicting stage of a collision, and shows the relationship betweensensors 81, 82, and 83 as the occupant seating information detectingmeans for achieving the retracting operation. As shown in the drawing,the information of an occupant “P” being seated on the seat 4, theinformation of the occupant physique, the seat sliding position, and thereclining angle is obtained from the sensors 81, 82, and 83. Theseinformation signals are signal-processed by the ECU 11 so as toestablish the optimum retracting length “ΔL” of the webbing “W” tothereby output an operational signal to the pre-tensioner 40 built inthe seatbelt take-up device 42.

That is, when it is determined by a collision predicting sensor 10 thatthe relative speed between the object to be impacted 8 and the equippedvehicle is greater than a predetermined speed and a collision willprobably occur within a short time, or when a danger level is determinedby the collision danger level determining means 12, the seatbeltpre-tensioner 40 is operated to thereby remove slack of webbing, whichis fitted to an occupant “P” before the collision, and further to applya predetermined tension to the webbing in a collision. This seatbeltpre-tensioner 40 is operated by a smaller set output to retract webbing.Accordingly, when a collision occurs, a moving occupant can beefficiently restrained and protected.

In the pre-tensioner 40, it is preferable that a piston/cylinder bedriven by using pressure fluid of a high-pressure source such as anexplosive power of explosives or an accumulator into which gas isaccumulated. Furthermore, a driving source such as an biasing mechanismusing a spring and an electrical motor may be used. Any part of thewebbing such as a shoulder-belt anchor portion, a slip-anchor adjusterportion, a waist-belt anchor portion, or a buckle may be available tohave such a mechanism besides the belt take-up device. The above partsmay have a such mechanism in combination. At the retracting time, it ispreferable that the pre-tensioner 40 be capable of retracting a webbinglength of about 200 mm.

As operational timing of the pre-tensioner 40, it is preferable that itbe driven at a moment (between 5 ms before a collision and at thecollision) when operation of the seat sliding mechanism 51 and the seatback reclining mechanism 52 in the seat adjusting mechanism 50 isfinished and a belted occupant is positioned in a most rearward positionwhich is the condition at which the webbing is drawn out the least.

CRS Reclining Mechanism

FIG. 12a is a schematic system diagram showing the reclining mechanism70, in which corrective operation of the reclining angle of the CRS 71installed to the seat 4 is performed in the collision predicting stageand it shows the relationship with the weight sensor 81 as the occupantseating information detecting means 80 for achieving the correctiveoperation. The installing direction of the CRS 71 and an infant seatingstate are detected by the weight sensor 81 within the seat face, andfurthermore, reclining angle information can be obtained from areclining angle sensor 73 within the CRS 71. The information issignal-processed in the ECU 11 so as to establish the correction angle“θ” of the reclining angle in the CRS 71 thereby outputting anoperational signal to the reclining mechanism 70.

FIG. 12b shows an oil pressure piston/cylinder being used as the drivingmeans 72 and is actuated by an operational signal from the ECU 11 sothat the reclining angle of the CRS 71 is corrected. As shown in thedrawing, the reclining angle can be established in stages by controllingthe extending length of the piston/cylinder 75.

As the driving means 72 of the reclining mechanism 70, a knownelectrical motor is suitable along with the oil or air pressurepiston/cylinder shown in FIG. 12a. As a reclining angle adjustingmechanism, it is preferable that a gear mechanism, a wiring mechanismvia pulleys, a link mechanism and the like be introduced in the CRS 71.These parts are operated and controlled by an operational signal fromthe ECU 11.

The controlling state and control characteristics of the CRS when itsreclining angle is corrected will be described with reference to FIGS.13 to 15.

FIG. 13a shows the forward-facing CRS 71 in an upright position whileFIG. 13b shows the CRS 71 reclined by the corrective operation of thereclining angle. By the correction, a seat face 71 a inclined to thecollision direction functions as a supporting surface so that part ofthe restraining load applied to the belt can be dispersed to the seatface 71 a.

On the other hand, as shown in FIGS. 14a and 14 b, when the CRS 71 isinstalled rearward-facing, the reclining angle is corrected (FIG. 14a)so that a seat back 71 b of the CRS 71 rises to a substantial uprightposition (FIG. 14b) by the corrective operation of the reclining angle.By the correction, impact applied to an infant is dispersed to the seatback 71 b.

FIGS. 15a and 15 b are control characteristic charts showing thecorrection amount of the reclining angle in the CRS 71 establishedaccording to the danger level. The danger level is determined by thecollision danger level determining means 12 at the collision predictingstage according to the installing state of the CRS 71 (forward facing:FIG. 15a, rearward facing: FIG. 15b). In the reclining mechanism, the“emergency level” (for example, when the relative velocity between anown vehicle and an object to be impacted is more than a predeterminedspeed, 10 to 20 km/h for example, while being collision-unavoidable bydriver's operation) is established as one threshold value. Furthermore,an intermediate setting position (angle), which is not such an emergencylevel, may be established as a second threshold value. The adjustmentamount of the reclining angle may also be changed on the basis ofcomputation of the relative velocity and the relative distance obtainedby plural times of detection.

We claim:
 1. A vehicle collision damage reduction system comprising:means for sequentially detecting distance information to an object to beimpacted moving relatively; means for determining a collision dangerlevel using the distance information; means for absorbing at least aportion of the collision energy to which a vehicle occupant is exposedto in a secondary collision following a vehicle collision; and means forcontrolling the collision absorbing energy means by outputting anoperational command, be ore the collision, on the basis of one of anobject detecting means and the collision danger level means, wherein thecollision energy absorbing means for a vehicle occupant is a mechanismfor shortening the steering column at least in part in the axialdirection, so as to increase the distance between the occupant and oneof the steering column and a shaft of the steering column.
 2. The systemof claim 1, wherein the shortening mechanism is introduced as part ofthe steering column.
 3. The system of claim 1, wherein loadcharacteristics of the shortening mechanism are adjustable in stages inresponse to the collision danger level.
 4. The system of claim 1,further comprising occupant seating information detecting means fordetecting the physique and a seating state of an occupant, and whereinan operational amount of the collision energy absorbing means for avehicle occupant is established by an operational command based on thephysique and seating state information.
 5. A vehicle collision damagereduction system comprising: an object detector for sequentiallydetecting distance information to an object to be impacted movingrelatively; a mechanism capable of shortening a steering column at leastin part in its axial direction, so as to increase the distance between avehicle occupant and one of the steering column and a haft of thesteering column; and an electronic control unit for determining acollision danger level using the distance information and or outputtingan operational command in response to the collision danger level toadjust the axial length of the steering wheel column.
 6. The system ofclaim 5, wherein load characteristics of the shortening mechanism areadjustable in stages in response to the collision danger level.
 7. Thesystem of claim 5, wherein the distance between the occupant and one ofthe steering column an the shaft is adjustable in stages in response tothe collision danger level.
 8. The system of claim 5, further comprisingan occupant seating information detector to detect physique and aseating state of the vehicle occupant, and wherein the length of thesteering wheel column is established by the operational command on thebasis of the physique and seating state information.
 9. A vehiclecollision damage reduction system comprising: an object detector forsequentially detecting distance information to an object to be impactedby the vehicle; and an electronic control unit for determining acollision danger level using the distance information and for outputtingan operational command, before the collision, to activate a safetydevice in response to the collision danger level, wherein the safetydevice further comprises a mechanism capable of shortening a steeringcolumn at least in part on its axial direction, so as to increase thedistance between a vehicle occupant and one of the steering column and ashaft of the steering column.
 10. The system of claim 9 wherein theshortening mechanism is introduced as part of the steering column. 11.The system of claim 9 wherein load characteristics of the shorteningmechanism are adjustable in stages in response to the collision dangerlevel.
 12. The system of claim 9 wherein the distance between theoccupant and one of the steering column and the shaft is adjustable instages in response to the collision danger level.
 13. The system ofclaim 9 further comprising an occupant seating information detector todetect physique and a seating state of an occupant, and wherein thelength of the steering wheel column is established by the operationalcommand on the basis of the physique and seating state information.